The agreement, which keeps health benefit costs flat for union members and aims to bring back workers laid off from shuttered eateries and belt-tightening buffets during the recession, passed with about 97 percent approval from participating members of Culinary Union Local 226 and Bartenders Union Local 165.

“This contract protects our benefits, and will help bring back jobs. It’s a good contract,” said Carlos Almazan, a kitchen steward at Mandalay Bay, in a statement. “I’m especially thankful to know my healthcare will be protected.”

MGM will contribute an additional 35 cents per employee, per hour in the first year of the contract, all of which will be used to cover the rising costs of a union-administered health benefits program. The contribution rises to 50 cents in the second year and 55 cents in the third, while the figure in the fourth and fifth years will be determined in further negotiations.

Workers could see the increased contributions as more take-home pay in the second and subsequent years of the contract, but that depends on whether health care costs can be kept under control.

Among other provisions, the contract allows housekeepers extra time to clean trashed hotel rooms, raises tips at banquet events from 18 percent to 19 percent by mid-2017, and requires the company give more advance notice when a worker’s immigration papers are about to expire.

The contract covers more than 21,000 union positions at Aria, Bellagio, Circus Circus, Slots A Fun, Excalibur, Luxor, Mandalay Bay, The Mirage, Monte Carlo and the New York-New York Hotel. Some of the terms would apply to about 5,000 additional workers at the MGM Grand Las Vegas, Signature and Vdara hotels.

Representatives from the union and MGM described the discussions as long but successful.

“Both sides have crafted an agreement that, despite difficult economic times, addresses the needs of Union workers and their families as well as those of the Company,” said Corey Sanders, MGM’s chief operating officer, in a statement. “We believe that’s what the Unions and the Company have achieved here: a smart contract, one that charts our Company’s future growth with the Unions.”

The settlement — the first the union has struck with a Las Vegas company since contracts expired citywide June 1 — is a major step forward for the Culinary Union. MGM employees account for about half of the powerful union’s 55,000 members.

Cutting a deal is a win for both sides, according to David Schwartz, director of the Center for Gaming Research at the University of Nevada, Las Vegas. It provides more labor certainty for MGM, he said, and is one less thing for the company to worry about.

In September, after contracts expired and the old ones were temporarily extended, the union issued a written warning to Wall Street investors saying a citywide strike was possible if agreements weren’t inked soon.

The last citywide strike occurred in 1984, when more than 17,000 workers protested 32 Strip resorts.

The Culinary Union is still in negotiations with all other casino companies except Wynn Resorts Ltd., according to spokeswoman Yvanna Cancela. About 20,000 members still do not have a new agreement with their employers.